Book binding machine



FIG. 1 is a front elevation of a book binding machine showing our new design;

FIG. 2 is a rear elevation thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right side elevation thereof;

FIG. 6 is a left side elevation thereof, and,

FIG. 7 is a front perspective view thereof. 

The ornamental design for a book binding machine, as shown and described. 